COLD AS ICE
Construction Hard hat safety air conditioned insert by NBD (COLDIE) CAI.
RICHARD COURTEMANCHE professor of Concordia university for neuroscience research said the cooling system is "EXCELLENT".
2 hours cooling before changing cartridge.
Averages on testings done 2014-2015
Temperature ranges. Outside temp. Inside helmet temp.
¼hour 34.1 22.5
1/2 hour 34.2 24.3
1 hour 34.3 27.2
1.1/4 hour 35.5 28
1.1/2 hours 35.6 28.3
1.3/4 hours 36.1 29.1
2 hours 36.2 30.7
Cerebral Changes During Exercise in
Bodil Nielsen and Lars Nybo
Institute of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark
Abstract This review focuses on cerebral changes during combined exercise and heat
stress, and their relation to fatigue. Dynamic exercise can elevate the core temperature
rapidly and high internal body temperatures seem to be an independent
cause of fatigue during exercise in hot environments. Thus, in laboratory settings,
trained participants become exhausted when they reach a core temperature of
~40°C. The observation that exercise-induced hyperthermia reduces the central
activation percentage during maximal isometric muscle contractions supports the
idea that central fatigue is involved in the aetiology of hyperthermia-induced
fatigue. Thus, hyperthermia does not impair the ability of the muscles to generate
force, but sustained force production is lowered as a consequence of a reduced
neural drive from the CNS. During ongoing dynamic exercise in hot environments,
there is a gradual slowing of the electroencephalogram (EEG) whereas
hyperthermia does not affect the electromyogram. The frequency shift of the EEG
is highly correlated with the participants’ perception of exertion, which furthermore
may indicate that alterations in cerebral activity, rather than peripheral
fatigue, are associated with the hyperthermia-induced development of fatigue.
Cerebral blood flow is reduced by approximately 20% during exercise with
hyperthermia due to hyperventilation,which causes a lowering of the arterialCO2
pressure. However, in spite of the reduced blood flow, cerebral glucose and oxygen
uptake does not seem to be impaired. Removal of heat from the brain is also
an important function of the cerebral blood flow and the lowered perfusion of the
brain during exercise and heat stress appears to reduce heat removal by the venous
blood. Heat is consequently stored in the brain. The causal relationship between
the circulatory changes, the EEG changes and the hyperthermia-induced central
fatigue is at the present not well understood and future studies should focus on
LEADING ARTICLE Sports Med 2003; 33 (1): 1-11
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